-
- Rules governing diplomacy and treaties among Greek city-states
- Roman concepts of ius gentium (law applicable to foreigners)
-
- Publication of De Jure Belli ac Pacis by Hugo Grotius
- First systematic treatment of international law
- Integration of natural law, treaties, and customary State practice
- Marks the beginning of international law as a coherent legal system
-
- End of the Thirty Years’ War
- Establishment of the sovereign State as the basic unit of international society
- Sovereignty and territorial independence become foundational principles of international law
-
- Growth of rules on:
Law of the sea
Diplomatic and consular relations
State responsibility - 1815 Congress of Vienna promotes regular diplomatic meetings
- Emergence of multilateral treaties and the first international organizations (river commissions)
- Growth of rules on:
-
- Increased use of multilateral conventions
- Creation of permanent international organizations with administrative functions
- Recognition that international cooperation requires stable legal institutions
-
- Establishment of the League of Nations after World War I
- Creation of the Permanent Court of International Justice (1920)
- Attempts to limit war and regulate new areas of international concern
- This period significantly advanced international legal norms
-
- Rapid expansion of international law into:
Human rights
International criminal law
Environmental law - Establishment of the International Law Commission (1947)
- Development of international law mainly through multilateral treaties and soft law
- Individuals increasingly recognized as subjects of international law
- Rapid expansion of international law into:
-
- Adoption and entry into force of the United Nations Charter
- Prohibition of the use of force
- Creation of the International Court of Justice as the principal judicial organ of the UN
- Expansion of international law into peace, security, and cooperation